A Search for Optical Laser Emission from Proxima Centauri

Left: Overplot of all 57 spectra of Proxima Centauri, zoomed near a wavelength of 4184.8 Å, of Proxima Centauri taken between 5 – 14 May 2013. The comb fringes appear at nearly the same wavelengths on all 10 nights, within ~0.05 Å, implying a Doppler drift <4 km s-1 . Right: The sum of the 57 spectra at the comb region. The fringes are nearly equally spaced by 0.175 Å and have shapes only slightly wider than the instrumental profile (Figure 2), indicating narrower intrinsic shapes.

A search for laser light from Proxima Centauri was performed, including 107 high-resolution, optical spectra obtained between 2004 and 2019. Among them, 57 spectra contain multiple, confined spectral combs, each consisting of 10 closely-spaced frequencies of light.

The spectral combs, as entities, are themselves equally spaced with a frequency separation of 5800 GHz, rendering them unambiguously technological in origin. However, the combs do not originate at Proxima Centauri. Otherwise, the 107 spectra of Proxima Centauri show no evidence of technological signals from lasers or any optical light in a narrow range of wavelengths.

This search would have revealed lasers pointed toward Earth having a power of 20 to 120 kilowatts and located within the 1.3au field of view centered on Proxima Centauri, assuming a benchmark laser launcher having a 10-meter aperture.

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)

Geoffrey W. Marcy

Cite as: arXiv:2102.01910 [astro-ph.EP] (or arXiv:2102.01910v1 [astro-ph.EP] for this version)
Submission history
From: Geoffrey W. Marcy [view email]
[v1] Wed, 3 Feb 2021 07:02:22 UTC (6,672 KB)
Astrobiology, SETI

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